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Numărul 11 al Revistei RECENT a fost:
CONTENTS
Vasile BEJAN, Rocsin Vasile BEJANFACTS ABOUT ENGINEER PROFESSION » Abstract. This paper is trying to present the engineer position within technological society of third millennium and the actual situation from Romanian economy. » Keywords: engineering, design, economy, production Adrian Virgil CRĂCIUN, George NICOLAEA NEW INDUSTRIAL METHOD FOR STRUCTURAL TESTING OF INTEGRATED CIRCUITS » Abstract. This paper presents an original method and a practical system implementation for testing virtually any kind of integrated circuit (IC). The testing method is based on the IC terminal characteristics plotting, by measuring few voltage-current pairs for all the IC terminal pairs. The testing system block diagram, some of the circuits schematics and some of theirs design formulae are presented. This testing method can be used in the industrial environment because of its advantages: the simplicity, the low cost, high testing speed and the testing system portability. The main disadvantage, specific to the structural testing methods, is the uncertain positive answer; to overcome this, some supplementary functional tests can be used. » Keywords: couplings, mechanical presses, design Bogdan DAVID, Valentin DIŢUTHE WORKABILITY ANALYSIS OF CERTAIN TITANIUM ALLOYS FOR AVIATION INDUSTRY, USING DECISION MODELLING METHODS » Abstract. The present study retrieves a set of conclusions taken from an analysis using two decision modelling methods under conditions of certainty (Onicescu Method and Global Utility Method). The objective of this analysis is to evaluate the workability of three selected Titanium alloys, most frequently used in aviation industry (TiMo32, TiAl6V4 and TiAl5Fe2,5). According to the evaluation hereunder, all the results are revealing the same hierarchy of workability properties for both the set of Titanium alloys, and the couple "machined alloy / tool". Thus, the results of both applied methods, are showing that the lowest workable alloy is TiMo32 comparing to TiAl5Fe2,5 (relatively the best), and the best suitable couple "machined alloy / tool" is TiAl5Fe2,5/K20, while the poorest is TiAl6V4/P20. A secondary conclusion is that the tool material having the poorest performance is P20, comparing to K20. » Keywords: cutting, workability, modelling, decision Monica FLORESCU, Laura Mihaela RABOPTICAL SENSORS USED IN VIABLE CELLS DETECTION » Abstract. The food and drink industries need rapid and affordable methods to assure the quality of products and process control, where the use of analytical methods such as high performance liquid chromatography (HPLC) or mass spectroscopy (MS) may be costly or laborious. Application of sensors and biosensors technique in the field of food processing and quality control is promising. Optical sensors offer advantages as alternatives to conventional methods due to their inherent specificity, simplicity and quick response. » Keywords: optical sensor, fluorescence quenching, oxygen detection, viable cells Cătălin GHEORGHEEVOLUTION OF THE MACHINE-TOOLS PRODUCTION IN ROMANIA AFTER 1990 » Abstract. Machine-tools constitute fundamentally factors for developing process. Machine-tools production represents an important segment of economic structure from developed economy. The paper presents some aspects from an analysis related production of machine-tools in Romania. » Keywords: production, import, export, trade balances, consumption, restructuring Lucian IULIAN, Ioan MATLACELECTRICAL PULSES TABLES PROCESSING PRECISION SYSTEM » Abstract. Studying electrical buck converter, the authors realizes a system to control with high accuracy the power transfer from a DC source to a coil load. In the paper the authors presents the particular relations obtained for the system buck converter-pure inductance load. They propose an application of this precision system to processing tables by electrical pulses. » Keywords: converters, choppers, RL load Vasile JIMAN, Virgil GEAMĂN, Florin STROE, Iulian ZAHARIANANOMATERIALS WITH CONTROLLED ION MOBILITY » Abstract. The paper presents some theoretical and experimental data about nanomaterials with controlled ion mobility – a very useful technology for scientists. There is presented also the theory of special chemistry techniques for obtaining these new advanced materials with special mechanical and technological properties. » Keywords: nanomaterials, ion mobility, sol-gel technique, circle ether, PEO Ioan LIHTEŢCHI, Vasile GHEORGHEUPGRADING OF HYDRAULIC DIRECTION CASE FOR BROADER USE » Abstract. The paper present a new model of hydraulic assisted direction case having screw – nut on sector balls assembly which was originated from 7235 servo assisted direction case used on four wheel drive ARO vehicles, for the range of axle load of 10-20 kN. The model was manufactured at Road Vehicle Institute (S.C. INAR S.A.) and the test procedures and results are presented. » Keywords: Servo-assisted direction case, endurance tests George NICOLAE, Adrian Virgil CRĂCIUN, Mihai ROMANCA, Gheorghe PANĂNOISE IN TV CHANNEL. NOISE MEASURING AT TV RECEIVER ENTRANCE (1ST PART) » Abstract. Statistics and probability calculus may be used in television to characterize noise in TV channels. This paper presents the experimentally results of noise measuring at TV receiver entrance. The paper first introduces the most important concepts in statistics and probability, emphasizing how they apply to acquired signals and noise. The experimentally measurements were concentrated onto determining the characteristics of the noise in UHF frequency band TV channels. The data acquisition system was used to measure various parameters of fluctuation noise at TV receiver entrance. These parameters are important in understanding the noise influence on the quality of received images. » Keywords: noise in television, noise in TV channel, fluctuation noise Marian PEARSICĂ, Mihai MIRON, Cristian CONSTANTINESCUMECHANICAL SHOCKS GENERATOR BASED ON PIEZOELECTRIC TRANSDUCERS » Abstract. This device constitutes a specific application of piezoelectric transducers, which allow the generation of mechanical shocks. The device work is based on the process of achieving of inverse piezoelectric effect, meaning the deformation of the crystalline network of the piezoelectric device caused by an external electrical field. The deformation power of piezoelectric transducer is approximately 450W. The dimensions and the composition of the piezoelectric transducers were determined depending on the working conditions and on the datum mechanical power. The equipment was physically realized and it constituted the object of a research contract of the Optical-Electronic Institute of Bucharest. » Keywords: mechanical shocks, piezoelectric transducers, electrical field, mechanical power Sorin PATER, Nicolae POLOJINŢEF-CORBU, Constantin BUNGĂUDUAL CHANNELS FLAW DIAGNOSIS OF GEARBOXES » Abstract. Paper presents double analysis of signals utilized for gearbox diagnosis. Cepstrum analysis was used in the purpose of flaw detection, by vibrations. » Keywords: gearbox, cepstrum, vibration, frequency Mihaela POPESCU, Constantin BUZATUUNCERTAINTY ESTIMATION AND REPORTING FOR FINISHED LEATHER CHARACTERISTICS AS RESULTS FROM THE LABORATORY FINAL TRIALS » Abstract. The paper presents the way of estimating and expressing uncertainty for the leather characteristics as results from the final laboratory trials in a tannery. After presenting theoretical considerations on this topic, the paper gives a working example for reporting one of the most specific characteristic of the finished leather, as this one decides the purpose of the product, that is its thickness. » Keywords: uncertainty estimation, uncertainty expressing, confidence level, finished leather, leather thickness Adela–Eliza ŞIMON, Dorin DUMITRAŞCUTHE RISK IN PROJECTS » Abstract. The risk is an inherent component of all activities of each project, irrespective a simple or a complex activity. This paper presents notions about risk, the different between risk and uncertainty, the ranking of risks and their impact on a project. » Keywords: risk, uncertainty, project Horia TÂRZIUTHE USE OF A SPECIAL DEVELOPED APPLICATION EMPHASIZING 2D PROJECTIONS » Abstract. The software application AutoCAD represents a high flexibility solution in data accessing and processing enabling the user to customize the front-end environment to meet specific requirements and needs. One of its components supports creating custom applications that can take advantage of AutoCAD reach interface. In this study it is utilized the high level language LISP to create custom software applications. This article presents several utilizations of a special developed application emphasizing 2D projections and technical graphics. Its results are applicable in any technical field with a special interest in graphical representations. » Keywords: programming, AutoLISP, 2D projections Ion VERZEATHE 5S OF TOTAL PRODUCTIVE MAINTENANCE: AN APPLICATION OF BARNES’ PRINCIPLES? » Abstract. The last decades have proved the Japanese superiority in improvement management, by applying original concepts, subsequently massively transferred to the western world. As examples the Total Productive Maintenance (TPM) should be mentioned, together with its three basic principles: Selfmaintenance, "5S", Productive Maintenance. At the same time, the western world demonstrates possibilities of technological innovation (technological leaps) superior to the Asian ones. Today the combination of the two directions represents the key to business success in the context of modernisation of markets, by a continuous growth of performances. It is to be remarked that R.M. Barnes’s principles of motions saving stated already in the 1940s (that is at least four decades prior the conceptualisation of the 5S) are consistently represented in the “5S” of TPM. The present study aims at analysing this phenomenon, demonstrating that the “5S” of the TPM are partially interrelated with R.M. Barnes’ principles. » Keywords: 5S, Total Productive Maintenance, technological innovation, Barnes’ principles Iulian Ioan ZAHARIA, Florin Victor STROE, Virgil GEAMĂNSTUDY CONCERNING THIXOFORMING OF METALLIC MATERIALS » Abstract. This paper presents a new method of semi-solid metal processing – thixoforming, which combines technological elements from several hot processing methods. Thixoforming is an efficient alternative for manufacturing of pieces which have finally shapes and sizes very closed to the functional status of these, and also, better physical and mechanical properties. » Keywords: thixoforming, rheoforming, thixocasting, processing of semi-solid metals
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